Implement context-menu for 3D viewport

[philippotto]

Detailed Description

The other viewports already have a context menu. For the 3D viewport the following actions could be interesting:

• all node-related context actions we already have in the other viewports
• mesh-related actions, such as:
  • jump to position
  • remove mesh
  • reload mesh
  • reveal mesh in sidebar (see #5792)
• settings (e.g., "hide wireframe")? we already have that via a settings icon, but a context menu might also be a good place.

Would make the 3D viewport easier to use.

Context

• [ ] Specific to long-running jobs (set jobsEnabled=true in application.conf)
• [ ] Specific to webKnossos.org (set isDemoInstance=true in application.conf)

[hotzenklotz]

Related to #6300 (Duplicate?)

[MichaelBuessemeyer]

@philippotto I have a short question :) Should I implement a remove or a hide action for meshes? Or both?

[philippotto]

Yes, good question! I'd say, "Hide" is more important, but if remove is easy (which I'd assume it is), let's add that too :)